The phase-cut dimming mode has some advantages. It is convenient for users to install and wire the circuit. Further, it is easy to convert the lighting circuit wiring in an old building into a lighting solution with a dimming function. Hence, the phase-cut dimming mode is more and more widely used. However, the input voltage range of the current phase-cut dimming power supply is narrow. For example, the input voltage range of the phase-cut dimming power supply which is suitable for the regions of China, Europe, Australia and etc. is within 170-265V, the input voltage range of the phase-cut dimming power supply which is suitable for the regions of North America, Japan and etc. is within 90-130V. Therefore, there is no phase-cut dimming power supply having an input range within 90-305V, which is suitable for most of electric networks in the whole world.